English Abstract Volume changes of the Greenland ice sheet in response
to climate change may form a significant contribution to variations in sea
level. However, still the sign of the present volume change is unknown.
The aim of this project was to increase our understanding of present state
of the Greenland ice sheet and of its sensitivity to climate change, with
emphasis on the Kangerlussuaq transect (West Greenland, 67 uN). We have
performed mass-balance, meteorological and ice-velocity measurements along
the transect. With a record length of 10 years, the mass-balance
measurements constitute the longest series of this kind on the Greenland ice
sheet. A crucial parameter for the determination of the amount of melt is
the albedo (this is the fraction of the solar radiation reflected by the
surface). Therefore, we have improved the retrieval methods used to
estimate the surface albedo from satellite data. For that purpose we have,
among others, measured the albedo from a helicopter. The resulting data
were used for validation of the satellite-derived albedos. With the
satellite-derived albedos and the mass-balance data we have developed a
method for estimating the surface mass balance of the Greenland ice sheet
from satellite data. Furthermore, we have developed an atmospheric
boundary-layer model, specifically designed for glaciers and ice sheets.
The model was used to study the relation between the climate of the free
atmosphere and conditions near the surface of the ice sheet, which determine
the amount of melt.